From: Zach Brown Date: Sun, 25 Jun 2006 12:46:46 +0000 (-0700) Subject: [PATCH] AOP_TRUNCATED_PAGE victims in read_pages() belong in the LRU X-Git-Tag: v2.6.18-rc1~1067 X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=commitdiff_plain;h=9f1a3cfcffaed2fbb3206179295c79ca8289f5c3 [PATCH] AOP_TRUNCATED_PAGE victims in read_pages() belong in the LRU AOP_TRUNCATED_PAGE victims in read_pages() belong in the LRU Nick Piggin rightly pointed out that the introduction of AOP_TRUNCATED_PAGE to read_pages() was wrong to leave A_T_P victim pages in the page cache but not put them in the LRU. Failing to do so hid them from the VM. A_T_P just means that the aop method unlocked the page rather than performing IO. It would be very rare that the page was truncated between the unlock and testing A_T_P. So we leave the pages in the LRU for likely reuse soon rather than backing them back out of the page cache. We do this by matching the behaviour before the A_T_P introduction which added pages to the LRU regardless of what ->readpage() did. This doesn't include the unrelated cleanup in Nick's initial fix which changed read_pages() to return void to match its only caller's behaviour of ignoring errors. Signed-off-by: Nick Piggin Signed-off-by: Zach Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/readahead.c b/mm/readahead.c index 0f142a4..4ee52ca 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -182,14 +182,11 @@ static int read_pages(struct address_space *mapping, struct file *filp, list_del(&page->lru); if (!add_to_page_cache(page, mapping, page->index, GFP_KERNEL)) { - ret = mapping->a_ops->readpage(filp, page); - if (ret != AOP_TRUNCATED_PAGE) { - if (!pagevec_add(&lru_pvec, page)) - __pagevec_lru_add(&lru_pvec); - continue; - } /* else fall through to release */ - } - page_cache_release(page); + mapping->a_ops->readpage(filp, page); + if (!pagevec_add(&lru_pvec, page)) + __pagevec_lru_add(&lru_pvec); + } else + page_cache_release(page); } pagevec_lru_add(&lru_pvec); ret = 0;